13s and 15mpg Magnum head 360

I agree with BJR* if your not going to purchase new parts. In what I would consider a better combo posted by Flyboy01 with the exception of the carb. The AVS style carb is really the same as the AFB in much of it's design, save the air door on the rear.
The new parts I think would do better. But you do have a shelf full of stuff.

* If you could tune the T-Q well, I myself would go there.

DGC's combo is really cool IMO. And works well. Though he has headers, not exhaust manifolds.
Tune the carb well, get that ignition timeing in well.